Crushing mill



Oct. 30, 1962 s. scHAUER ErAL 3,061,208

CRUSHING MILL Filed July 15. 1959 2 sheets-sheet 1 Hg. 42 F/g F/g. 7

Oct. 3o, 1962 S SCHAUER ETAL 3,061,208

CRUSHING MILL Filed July 15. 1959 2 Sheets-Sheet 2 United States Patent O 3,061,208 CRUSHING MILL Siegfried Schauer, Kohlkopfstr. 6, Hohenecken, Pfalz,

Germany, and Hans Kihm, Kirschenstr. 1, Kaiserslautern, Pfalz, Germany Filed July 13, 1959, Ser. No. 826,731 Claims priority, application Germany July 15, 1958 7 Claims. (Cl. 241-117) The present invention relates to a crushing mill of the type in which a plurality of grinding rolls which are rotatably mounted within the mill housing are pressed by springs and an intermediate pressure-transmitting member in a vertical direction upon a rotating grinding surface.

There have been prior disclosures of various constructions of crushing mills employing crushing or grinding rolls for grinding or pulverizing different materials. Thus, for example, there have been crushing mills in which the pressure-transmitting member `consisted of a ring which acted upon all of the grinding rolls which traveled in a planetary movement underneath the ring. Since the pressure-transmitting ring rested directly on the grinding rolls `or on suitable projections thereon, not only the grinding rolls but also the ring acting thereon became worn in the operation. In Order to reduce such wear as much as possible, it was necessary to make the pressuretransmitting ring and the grinding rolls of a high-quality steel. Although this increased the length of service of the grinding rolls and the pressure-transmitting ring, they still had to be both exchanged when worn, rendering the cost of operation of this type of crushing mill very high.

In another known type of crushing mill, the grinding rolls were rigidly connected by means of a supporting member to a non-rotatable pressure-transmitting ring which was guided s'o as to be movable in a vertical direction. Although in this type of construction the wear between the ring and the grinding rolls was eliminated, it had the disadvantage that, if one of the grinding rolls was lifted off the grinding surface against the spring pressure, for example, because of an accumulation of material thereon, this meant that the other grinding rolls were automatically also lifted off the grinding surface and thus did not exert any grinding or crushing action upon the material thereunder.

In a further known type of crushing mill, each grinding roll was mounted separately on a -system of levers through which the spring pressure was transmitted to the individual roll. Thus, each grinding roll could yield individually in the upward direction. However, this type of construction had the disadvantages that the pressuretransmitting members were subjected to very severe stresses and particularly that, due to the lever transmission, the grinding pressure was not constant along the width of the grinding surface and the grinding eiciency decreased considerably when the grinding rolls became worn at one side.

All of these known constructions of crushing mills had the further disadvantage that the grinding rolls thereof, which were disposed in a substantially vertical position relative to the grinding surface, could only move in a vertical, more or less rectilinear direction, that is, within the central plane of each roll. Consequently, if the grinding rolls had to yield in the upward direction because of an accumulation of material on the grinding surface, the eifective contact surface of the grinding rolls and thus f ICC able means for mounting the same above the grinding surface so as to be pivotable on the pressure-transmitting member in a direction transverse to the central plane of the grinding roll. This is attained according to the invennon by mounting the axle of each grinding roll on a suspension member which is fulcrumed on the pressuretransmitting member. The bearing is preferably formed by providing corresponding surfaces of revolution on the pressure-transmitting member and the roll-suspension member, One of these two associated surfaces of revolution is preferably formed on a bearing member which is connected to the pressure-transmitting member and preferably exchangeable, while the opposite surface of revolution is formed by a bearing section or shell which is mounted on the roll-suspension member. Of course, the relative position of these two surfaces of revolution or bearing surfaces on the roll-suspension and pressuretransmitting members may also be reversed.

This additional pivotable mounting of the grinding rolls on the pressure-transmitting member permits them to move not only in a vertical direction but to a certain extent also in the lateral directions so that, if the material to be ground or crushed accumulates on the grinding surface at one side of the rolls, each individual roll can yield in a lateral direction toward the smaller amount of material. Thus, the effective contact or grinding surface -of the roll will be less diminished than in conventional arrangements.

If the pressure-transmitting member is made in the form of a ring which acts upon all of the grinding rolls, this additional pivotable mounting of the rolls on the pressure-transmitting member has the further advantage that each individual roll can yield in the upward direction without affecting the position of the other rolls and without thereby lifting them olf the grinding surface. If one of the grinding rolls is lifted for some reason, the pressure-transmitting ring will only yield upwardly within the area of this roll, while its other parts will, through the pivotable mounting, remain in engagement with the other rolls so that these other rolls will remain under pressure on the grinding surface and continue to exert their full grinding action.

By providing separate bearing members betweeen the pressure-transmitting member and the roll-suspension member, these bearing members may be easily exchanged when worn so that it will not be necessary to exchange the grinding or crushing efficiency thereof was reduced,

the entire pressure-transmitting member and possibly even the grinding rolls as it was necessary in previous crushing mills -of this type.

The above-mentioned and other objects, features, and advantages of the present invention will now be described in detail with reference to the accompanying drawings, in which- FIGURE 1 shows a vertical cross section on the line lA-Al of FIG. 2 of a crushing mill according to the lnvention;

FIG. 2 is a top plan view of the pressure transmitting ring of FIG. l;

FIG. 3 shows in perspective one of the parts;

FIGURES 4 to 7 show cross sections similar to FIG- URE 1 of different modifications of the invention (FIG. 5 being a section on the line B-B of FIG. 8);

FIGURE 8 shows a plan view of the grinding rolls and illustrates the manner of guiding them to move in a vertical direction according to FGURES 5 to 7.

All of the embodiments of the invention as illustrated in the drawings have in common that the grinding rolls 1 which may be provided in any suitable number, for example, three, are mounted at substantially ltixed radial positions with the axes each in a substantially fixed vertical plane, within a housing 2 and act under a resilient pressure upon a grinding plate 3. which is rotated by a suitable drive mechanism 4 so that the grinding rolls 1, engaging with grinding plate 3 within an annular groove 5 in the upper surface of the latter, will roll along this groove. According to the embodiments as illustrated in FIGURES 1 and 4, each grinding roll 1 is loaded by springs 6, the upper ends of which bear against a stationary ring 7 which is connected as by welding to the inner wall of housing 2, while the lower ends of these springs act in the downward direction upon a pressure-transmitting ring 8 to which straight bearing members 9 are secured by conventional means. Each of these bearing members 9 has a partly cylindrical bearing surface 9 engaging in a shell or socket 10 with a corresponding bearing surface 1G. Each shell 1Q is secured to. one end of a roll-suspension member 11 which carries on its other end an axle 12 on which the grinding roll 1 is rotatably mounted. The associated bearing surfaces 9 and 10 form a bearing which permits each grinding roll 1, apart from the vertical reciprocating movements as indicated in FIGURE 1 by the arrow S, also to carry out a pivotal movement in a direction transverse to the central plane E of roll 1, as indicated by the arrow Q.

Grinding rolls 1 may be guided in different manners in a vertical direction as well as in the direction of rotation or" grinding plate 3. The spring pressure of springs 6 will thus be transmitted from ring 8 upon the two-armed lever forming the roll-suspension member 11 which prevents the respective roll 1 from escaping either forwardly or rearwardly in the direction of rotation of grinding plate 3, since escape would involve lifting of the roller out of the groove in the grinding plate onto the shoulder, and the springs resist this movement and thus exert a restoring force tending to keep the rolls in proper position.

As illustrated in FIGURES to 8, the axles 12 of the individual rolls 1 may, however, also have atted ends guided in slide bearings 13 which are spaced vertical plates mounted at one side on the inner wall of housing 2 and at the other side in slide bearings 14 which are spaced vertical plates on a central core member 14. These slide bearings 13 and 14 are designed to allow the required pivotal movement of rolls 1 about straight bearing members 9. The roll-suspension member 11 then only has to be connected to bearing member 9 by a single bearing shell 1G.

Instead of providing a common pressure-transmitting member in the form of the ring 8 and securing all of the bearing members 9 thereto, the apparatus may also be modified as illustrated in FIGURE 4 so that a separate pressure-transmitting member in the form of a one-armed lever 15 may be provided for each grinding roll 1. These levers 15 are pivotable within vertical planes by being mounted on bearings 16 which are secured to the inner wall surface of housing 2. Springs 6 acting upon levers 15 may then bear with their upper ends either upon a common supporting ring 7 in the same manner as shown in FIG- URES 1 to 3 or each individual spring 6 may bear upon a separate bracket 18 which is mounted on the wall of housing 2, as illustrated at the right side of FIGURE 4. Each lever 15 again carries a bearing member 9, the semicylindrical surface 9 of which bears upon the corresponding surface of a bearing shell 10. The pressure members 9 may in any of the embodiments of the invention either be removably secured to or integral with the pressure-transmitting ring 8 or the lever 15, or they may form cylindrical rollers which are resting in corresponding arcuate recesses in ring 8 or lever 15, as illustrated at the left side of FIGURE 4.

Instead of mounting the axle 12 of each grinding roll 1 only at one side thereof on a roll-suspension member 11, the latter may also be made in the form of a bifurcated member 19, as shown in FIGURE 4, so that the axle 12 will be supported at both sides of each roll 1.

Although our invention has been illustrated and described with reference to the preferred embodiments thereof, we wish to have it understood that it is in no way limited to the details of such embodiments, but is capable of numerous modifications within the scope of the appended claims.

Having thus fully disclosed our invention, what we claim iS:

1. A crushing mill comprising a stationary housing, a grinding plate within said housing, means for rotating said grinding plate about a vertical axis, a plurality of grinding rolls rotatable about individual axes each located in a substantially fixed vertical plane, vertically acting spring means, at least one pressure-transmitting member, said vertically acting spring means operatively engaging at one end a fixed part of the said housing and operatively engaging at the other end said pressure-transmitting member to exert a substantially vertical pressure thereon, and means fulcruming each of said rolls above said grinding plate on said pressure-transmitting member so that each of said rolls will be resiliently pressed upon said grinding plate and is adapted to move resiliently in a vertical direction and also to swing about said pressure-transmitting member in a direction substantially transverse to the central plane of said roll.

2. A crushing mill as defined in claim 1, in which said pressure-transmitting member comprises a single ring, all of said spring means acting upon said ring, said fulcruming means comprising a plurality of supporting members, each of said grinding rolls being rotatably mounted at one end of one of said supporting members, and a plurality of bodies forming pairs, one body of each pair being mounted on said ring, and the other body being mounted on the other end of said supporting member and adapted to receive said first body and together with said supporting member and grinding roll to be slidable on said -rst body in a swinging movement in a direction ysubstantially transverse to the central plane of said roll.

3. A crushing mill as defined in claim 2, in which each of said grinding rolls is rotatably mounted on a shaft, and bearing means mounted within said housing for supporting said shaft, said shaft being slidable Within said bearing means.

4. A crushing mill as defined in claim 1, having a plurality of pressure transmitting members, wherein said fulcruming means comprise a plurality of supporting members, each of said grinding rolls being rotatably mounted at one end of one of said supporting members, and associated bearing means on the other end of said supporting member and on each said pressure-transmitting member and engaging with each other for swingably fulcruming each of said rolls individually on said pressure-transmitting members.

5. A crushing mill as defined in claim 4, in which each of said grinding rolls and the supporting member thereof are associated with a separate pressure-transmitting member, each of said pressure-transmitting members forming a lever pivotably secured at one end to the wall of said housing and carrying at the other end one of said bearing means.

6. A crushing mill as defined in claim 2, in which said supporting member is bifurcated, said grinding roll being disposed between the two arms of said member and rotatably connected thereto.

7. A mill as claimed in claim 1 in which said fulcruming means include shafts on which said rolls are mounted, said pressure-transmitting member transmitting pressure through said shafts to the rolls.

References Cited in the file of this patent UNITED STATES PATENTS 1,049,051 Clark Dec. 31, 1912 2,689,689 Engler Sept. 2l, 1954 FOREIGN PATENTS 201,726 Australia Aug. 18, 1955 771,185 Great Britain Nov. 7, 1955 804,811 Great Britain Nov. 26, 1958 855,765 France Feb. 26, 1940 

